It should only disconnect if either a certain number of requests fails to reach the client; or no successful messages have been sent over >10 minutes, while there have been failures during that time.
The actual implementation/behaviour is from the tornado.websocket library, albeit we use a slightly older version of Tornado.
If you do have the time to investigate further we would quite welcome the feedback. We have put this on our list of things to improve in the future, but right now I can't give you any more specifics.